INTRODUCTION Literature abounds with evidence of toxicity of crude oil in laboratory animals; and, crude oil has been implicated as a developmental toxicant in laboratory animals. This study therefore was conducted to determine the behavioural teratogenic effects on the mouse offspring of dams gavaged Bonny light crude oil.
METHODS
The behavioural teratogenic effects of prenatal crude oil exposure on some parameters in the albino mice were assessed. Twenty virgin female albino mice weighing between 35g to 38g were used for this study. The animals were divided into 3 groups of 10 mice each (A and B). The females were caged overnight with sexually mature male mice of the same strain and the positive day was designated as day zero of gestation. Dams in group B and C were gavaged with crude oil (1ml/kg and 2ml/kg body weight, respectively) on gestation days 9 – 12. Dams in group A which served as control received only distilled water on corresponding days. Before weaning the offsprings were examined to test their surface righting reflex (5 days of age), cliff avoidance response (6 days) and negative geotaxis response (7 days). After weaning, they were examined using rotarod, the open field maze (7 weeks), and the shuttle- box-avoidance learning test.

RESULTS The results showed that the performance on the rotarod and the avoidance learning of the mice in the treatment group C was significantly poorer than that of the control group A. There were also significant differences between group A and C offspring for the surface righting, cliff avoidance and negative geotaxis responses. Results also indicated decrease in locomotor and exploratory behaviours of the treated groups.

DISCUSSION The findings suggest that prenatal exposure to crude oil may retard early response development; impair learning ability and development of motor coordination; as well as decrease in locomotor and exploratory behaviours of offspring of albino mice.

FINAL SUMMARY Prenatal exposure of mice to crude oil at a dose lower than that which cause gross malformation or growth retardation altered neurobehavioral performance in the offspring.